This formula describes how the practice of sampajañña has to be undertaken, but it does not defines the term. The real definition of being 'sampajāno' - word whose meaning is also otherwise described by the present formula - is found here; it makes it clear that being 'sampajāno' involves the discernment of aniccā. This formula appears in only three contexts: 1) in 3 suttas (DN 22, MN 10, MN 119), it is a part of the description of 'kāyānupassanā' or 'kāyagatāsati'; 2) in 6 suttas, it is associated with the definition of sato when the Buddha exhorts the bhikkhus to remain satos and sampajānos; 3) in 26 suttas of DN and MN, and 2 suttas of AN, it is a step on one version or the other of the Sekha Paṭipadā.